Wiper for stepping switch



Sept. 17, 1957 2,806,925

D. N. M DONALD WIPER FOR STEPPING SWITCH Original Filed July 30, 1953 2Sheets-Sheet 1 FIG. 24 66 4 a7 INVENTOR. I umwmmo Anoe rs Sept. 17, 1957D. N. M DONALD WIPER FOR STEPPING SWITCH Original Fild July so, 1953 2Sheets-Sheet 2 V I m :m /6.4

A TTORNEKS ou/vcmv 1v. MMDd/VALD IOA J United States Patent WIPER FORSTEPPING SWITCH Duncan N. MacDonald, Arcadia, Califi, assignor, by mesneassignments, to Consolidated Electrodynamics iglorporation, Pasadena,Calif., a corporation of Caliorma Original application July 30, 1953,Serial No. 371,372. Divided and this application October 18, 1954,Serial No. 462,697

2 Claims. (Cl. 200==166) This invention relates to improvements inwipers for stepping switches.

This application is a division of my co-pending applicatign SerialNumber 371,372 which was filed on July 30, 1 53.

The parent application discloses and claims a stepping switch whichcomprises a supporting framework, a drive shaft journaled through a wallof the framework, a bank of contacts mounted on an outer face of thewall of the framework, wipers mounted on the outer end of the shaft anddepending therefrom in engagement with the contacts, a ratchet wheelmounted adjacent the inner end of the shaft, first and secondelectromagnets mounted to the framework on opposite sides of the innerend portion of the shaft, first and second armatures pivotally mountedto the framework and respectively in operative association with thefirst and second magnets, first and second pawls pivotally mountedrespectively to the first and second armatures and engageable with theratchet wheel at respectively opposite extremities of a chord thereof,means operable to load both pawls and armatures, and means operableresponsive to displacement of each armature to open the electricalcircuit of the associated electromagnet.

The present invention relates to wipers which are particularly useful instepping switches of the type disclosed in the parent application.However, the wipers may be employed in other type switches.

The wipers of the present invention are arranged to provide bothflexibility and reliable support for the movable electrical contact ofthe wiper.

The wiper comprises an annular hub having integrally formed armsextending from opposite sides of the hub, with the outer ends of thearms being joined by an integrally formed control strip. The contactstrip and the adjacent portions of the arms are slotted to providegreater flexibility. By locating the electrical contact of the wiper ona strip which is integral with and located between the support arms,reliable support is provided for the electrical contact under alloperating conditions. Also, the slotted contact: strip providesindependent twin electrical contacts which enhance the reliability ofoperation of the wiper.

The invention is explained with reference to the drawings, in which:

Fig. l is a plan view of a switch of the type disclosed in the parentapplication, employing the wiper elements of the present invention;

Fig. 2 is a partial front elevation of the switch of Fig. 1 showing oneof the wiper elements;

Fig. 3 is a transverse section taken on the line 33 of Fig. 1;

Fig. 4 is a longitudinal section taken on the line 4-4 of Fig. 1;

Fig. 5 is an elevation view of one wiper element; and

Fig. 6 is a partial simplified circuit diagram showing one manner ofutilizing the switch.

Referring to the drawing, the switch elements are supported on aframework 10 which includes a base 10A 2,806,925 Patented Sept. 17, 1957and a front wall 10B extending perpendicularly to the base. A secondaryframework 12 is supported on the wall 10B of the framework 10 andincludes brackets 12A, 12B extending perpendicularly to the rear face ofwall 1013. A pair of electromagnets 13, 14 are mounted respectively inthe brackets 12A, 12B. An armature 15 is pivotally mounted to bracket12A adjacent magnet 13 and an arma ture 16 is pivotally mounted tobracket 12B adjacent magnet 14.

As shown most clearly in Fig. 3, armature 16 comprises twoperpendicularly disposed arms 16A, 163, the arm 16A underlying magnet 14and being referred to as the clapper, and the arm 16B extendinggenerally parallel to the axis of the magnet and being referred to asthe driving arm. At the lower end of the arm 16B the armature includesan extension which is pivotally mounted to a support block 1d, thesupport or armature mounting block in turn being mounted to the bracket1213. To provide proper lateral adjustment of the armature 16 thesupport block may be shimmed with respect to the bracket 12B, a singleshim 19 being shown. Along the inner vertical edge of arm 16B a pair ofspaced teeth 16D are formed. The function of these teeth is laterexplained.

A pawl 26 is pivotally mounted to the upper extremity of armature arm16B. Pins 22, 22A are mounted to armature arm 16B above pawl 20 andextend outwardly therefrom respectively in opposite directions from bothsides of the armature arm. Pin 22 carries a roller 22C held thereon by anut 24. The pawl 20 includes a tooth 20A extending inwardly fromarmature 16, an upwardly extending arm 20B and a downwardly extendingarm 26C, both disposed on opposite sides of the pivot point of the pawlfrom tooth 20A. Arm 20B of the pawl is adapted to engage against pin 22Ato act' as a limit to the counter-clockwise rotation of the pawl asviewed in Fig. 3. This pin has a carnmed cylindrical surface by means ofwhich the pawl is adjusted. Armature 15 is identical to pawl 20 andincluding an inwardly extending tooth 25A, an upwardly extending arm25B, and a downwardly extending arm 25C, the two arms again beingdisposed on opposite sides of the pivot point of the pawl from tooth25A. An armature pin 23 is identical to the pin assembly described indetail in relation to armature 16.

A linear U-shaped spring 26 is connected at its extremities to dependingarms 20C and 25C of the respective pawls. The spring. is generallyU-shaped with its base extending transversely of the rotational axis ofthe armatures. As previously mentioned, this spring urges therespectively engaged arms of pawls 20, 25 and also armatures 15 and i6outwardly, i. e., away'from the center plane of the switch.

A sleeve 28 is mounted through wall 10B of the framework extendingrearwardly therefrom generally parallel to the base and perpendicularlyto the front wall. The sleeve has a depending flange 28A which-isanchored to the framework 10 and against rotary displacement asillustrated in Fig. 4. A tubular axle 29 is coaxially mounted within thesleeve extending outwardly from the rear end thereof. A ratchet wheel 30is mounted on the projecting end of the axle 29. A shaft 32 is journaledthrough the tubular axle 29 extending outwardly from the front face ofwall 10B and rearwardly of the ratchet wheel 30. Nut 33 holds the wiperassembly on an end of the shaft 32 and nut 34 binds the axle 29 to theshaft so that when thus locked they rotate in unison. However, releaseof the locking arrangement permits relative rotation of the shaft 32 andaxle 29 for the purposes above described.

The ratchet wheel 30 is toothed around its periphery and carries a pairof rearwardly extending pins 36, 37.

A spring detent 38 is supported from the secondary framework 12 inengagement with the periphery of the ratchet wheel. The pawls 20 and 25are in transverse alignment with the ratchet wheel so that pivotaldisplacement of the respective armatures responsive to energization ofthe respective electromagnets engages one or the other of the pawls withan aligned tooth of the wheel, displacement of the armature being suchthat the wheel is driven one step, i. e., through an angular rotationequal to the angle included between the center lines of adjacent teethfor each actuation of the armature. Teeth 16D on armature 16 and thecorresponding teeth on armature 15 engage and lock the ratchet wheel atthe extremity of armature travel to prevent overdrive of the ratchet.The detent 38 prevents counter-rotation of the ratchet wheel uponretraction of the respective driving pawls.

It is apparent from the drawing that the two armature and pawlassemblies drive the wheel in opposite directions when separatelyenergized. V

A plurality of arcuate arranged banks of contacts 40 are mounted on thefront face of framework wall 103. These contact banks are conventionaland any number within the limits of the power capacity of the switch maybe incorporated.

A plurality of wipers 42, equal in number to the number of contactbanks, are mounted on the outboard end of shaft 32 and are insulatedfrom each other and from the shaft by an insulating washer 43. Thewipers are unique in shape and provide at the same time a maximum degreeof flexibility and a maximum support at the contact tip.

One of the wipers 42 is shown in elevation in Fig. 5 and comprises anannular hub 42A from which a pair of flexible arms 42B, 42C dependsupporting a contact tip 42D between the outer extremities. The arms areconnected to the hub 42A at their upper extremities on the opposite sideof the hub from the contact tip, and a continuous slot 42E extends alongthe extremity of each arm and across the contact tip. A high degree offlexibility is imparted by the slot 42B and by the connection of thearms at the upper part of hub 42A, and extra support of the contact tipis supplied by virtue of disposition thereof between the extremities ofthe two arms. The slotted tip additionally provides independent twincontact action.

The electrical circuit of the magnet is shown schematically in Fig. 6and includes a number of switches actuated by the respective armatures.The circuit of Fig. 6 is described with relation to magnet 13 andarmature. 15 as illustrated in Fig. 3. An input signal is connectedacross terminals 46, the circuit being closed by a control switch 47externally of the stepping switch, the control switch 47 beingfrequently manually operated. The input signal is fed through switch 47to a dipole switch 48 which includes a bus 48A and spring switch arms48B, 48C, the switch normally'being closed through the arm 48B asillustrated. The arm 48B of switch 48 is connected to a second switch 50including a bus 50A and spring switch arms 50B, 500, the connection fromswitch arm 48B being to the switch arm 50B of switch 50. The bus 50A ofswitch 50 is connected through magnet 13 to one of the input terminals.

With switch 47 closed an input signal will energize magnet 13 causingthe described displacement of armature 15 whereupon the armature pin 23releases arm C allowing it to make contact with bus 50A and immediatelythereafter springing arm 5013 to break that contact. The arm 50C acts asa so-called'preliminary make-switch preventing ambiguity of armaturetravel. The loading spring 26 returns the armature to its retractedposition and as long as the input signal remains across the terminals 46the armature will repeat this process, stepping the ratchet wheel ateach cycle until pin 37 on the ratchet wheel strikes against bus 48A ofthe switch 48 and displaces it from the switch arm 48B. This opens themagnet circuit and at the same time closes a circuit through switch arm48C whereby a signal may be fed from the switch through so-called carryterminals 52 to indicate this condition. The circuit associated with theother magnet 14 is identical, as is the arrangement of the associatedswitches corresponding to switches 48 and 50 as described.

Rotation of the ratchet wheel responsive to actuation of the respectivearmatures induces like rotation of the wipers effecting a step-wisedisplacement of the wiper contact point along the several arcuatelyarranged contacts in the contact bank.

Stepping switches of this type find extensive use in many applicationssuch as counting, data handling, and the like, such applications formingno part of the present invention. As previously mentioned, the outboardarrangement of the wiper assembly and the shaft 32 upon which theassembly is supported permits the switch to be readily converted to astepping motor.

I claim:

1. A wiper for a stepping switch comprising a hub, a pair of arms joinedto one side of the hub and extending freely therefrom in oppositedirections around the major portion of the periphery of the hub, thearms being disposed substantially in the plane of the hub, the armsbeing joined together at the side opposite that at which they are joinedto the hub, both arms being slotted longitudinally at the ends wherethey are joined to each other to form two coextending arm portions for alength which circumscribes a minor portion of the periphery of the hub.

2. A wiper for a stepping switch comprising an annular hub, a pair ofarms joined to the hub at a common location on one side of the hub andextending freely from the hub in opposite directions around the majorportion of the periphery of the hub and substantially in the plane ofthe hub, the arms being joined together end to end at the side oppositethat at which they are joined to the hub, both arms being slottedlongitudinally at the ends where they are joined to each other to formtwo coextending arm portions for a length which circumscribes a minorportion of the periphery of the hub, and contacts disposed on said twoarm portions.

References Cited in the file of this patent UNITED STATES PATENTS

